discord_send_message

THE RISK

Medium Risk

Why discord_send_message needs a policy

This tool creates new data (Discord messages) in a reversible manner. It modifies server state by adding messages but does not delete, execute code, move money, or cause irreversible damage.

From the tool's definition Tool description explicitly states 'Send a message to a Discord channel' and 'Returns the sent message ID', indicating message creation. The server description confirms 'message management' and 'sending messages' as core capabilities.

Documented attack patterns abuse exactly the kind of access discord_send_message gives an agent:

POLICY

How to control discord_send_message

PolicyLayer is an MCP gateway — it sits between your AI agents and Discord User, and nothing reaches the server without passing your rules. This is the rule we recommend for discord_send_message:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "discord_send_message": {
      "limits": [
        {
          "counter": "discord_send_message_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

discord_send_message stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

Create a free account and register Discord User — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More Discord User tools

Destructive discord_delete_message Delete one of your own messages. This action is permanent and cannot be undone. Write discord_edit_message Edit one of your own messages. You can only edit messages you sent. Write discord_react Add a reaction emoji to a message. Use standard unicode emoji or custom emoji in name:id f Write discord_send_dm Send a direct message to a user. Provide user_id to open a new DM, or channel_id if you al Read discord_find_message Find messages in a Discord server by author, content, or date range. Tries guild search fi Read discord_get_replies Get all replies to a specific message. Fetches messages after the target and filters for t Read discord_guild_info Get detailed information about a Discord server: name, description, member count, roles, a Read discord_list_channels List channels in a Discord server, grouped by category. Use DISCORD_DEFAULT_GUILD env var

All 16 Discord User tools →

Write tools on other servers

M-Team MCP Server download_torrent YouTube MCP Server generate_video_title Android Forensics ADB MCP Server combine_reports 0xarchive web3_signup

Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Argument validation → Checking tool call arguments against schema and policy before they run.
Scoped token → Per-person credentials that grant a defined subset of servers and tools.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about discord_send_message

What does the discord_send_message tool do? +

Send a message to a Discord channel. Supports plain text and Discord markdown (bold, italic, code blocks). Returns the sent message ID. It is categorised as a Write tool in the Discord User MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on discord_send_message? +

Register the Discord User MCP server in PolicyLayer and add a rule for discord_send_message: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Discord User. Nothing to install.

What risk level is discord_send_message? +

discord_send_message is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit discord_send_message? +

Yes. Add a rate_limit block to the discord_send_message rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block discord_send_message completely? +

Set action: deny in the PolicyLayer policy for discord_send_message. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides discord_send_message? +

discord_send_message is provided by the Discord User MCP server (olivier-motium/discord-user-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Discord User tool call.

Start from Discord User, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →